Open pot oil burner with unbalanced air supply



NW0 2, 1%. L. D. MILLS OPEN POT OIL BURNER WITH UNBALANCED AIR SUPPLY Filed June 50. 1947' 2 Sheets-Sheet\1 avwe/Mo'u jean .aj fz'lls.

Nova 2, 1948. I... D. MILLS OPEN POT OIL BURNER WITH UNBALANCED AIR SUPPLY Filed June 30, 1947 2 Sheets-Sheet 2 lif- Patented Nov. 2, 1948 OPEN POT OIL BURNER. WITH UNBALANC AIR SUPPLY Mills, Tacoma, Wash. Application June so, 1947, Serial No. 758,075

' The invention relates to open pot oil burners of the generaltype in which the oil burning pot is 1 enclosed by an airsupply jacket which receives air under pressure from a blower. the side wall of the pot being formed with primary and secondary Claims. ((1158-91) air inletopenings for conducting air from said jacket into the pot to support combustion. The primary air inlet openings are near the bottom of i the pot and have the function of supporting sufllcient combustion in this region to heat the pot for vaporization of oil and to maintain a pilot or low fire. The secondary air inlet openings are above the primary openings and admit all other air necessary for complete combustion of all oil vapors.

While burners of the type in question are operating at high flame, the flow of oil tends to build up and form a puddle on the pot bottom, and when the air and fuel supply meansare adjusted (usually synchronously) for low flame, this pool of oil is left to be burned, but the supply of primary air to this pool is then insuflicient to support complete combustion of such a large amount of oil, with the result that the burner smokes and forms soot and carbon. Other burners of this type are also limited as to the maximum amount of oil which can be vaporized and burned cleanly and still maintain a clean low pilot flame.

My invention provides animproved burner which will consume all oil admitted to the pot during high flame operation and which will burn a greater amount of fuel on high flame than conventional burners of the same size while still having the ability to operate on a very low pilot flame and the ability to change from high flame to low flame without the period of improper combustion foundin other burners of this type. I attain this result by a novel construction which injects a much greater amount of air through the primary air inlet openings than usual during high flame operation. and shields the pot bottom against the cooling effect of the air being rapidly blown into the air jacket. By so doing. greater combustion occurs in the bottom zone of the pot and its temperature is maintained suiiiciently high torapidly vaporize the oil for thorough burning instead of allowing a pool to accumulate; and with a relatively small burner, I am enabled to produce a greater range of heats than heretofore. possible with this type of burner. V

Figure l of the accompanying drawings i a vertical sectional view on line of Fig. 3.

Fig. 2 is an enlarged fragmentary vertical section similar to the lower left portion of Fig. l.

Fig. 3 is a view partly in top plan and partly in horizontal section, as indicated by line l- -3 of Fig. 1.

to be understood that minor variations may be made within the scope of the invention as claimed.

A pot 5 is shown having a centrally depressed bottom 6 and a cylindrical side wall I, said side wall being provided with an oil inlet 8 near its lower end and having a lateral continuous flange 9 at its upper end. An upper burner ring in rests on this flange 9, and a lower burner ring I rests on lugs or the like l2 projecting inwardly from the lower portion of the side wall]. Below the lower ring II, the side wall I is formed with circumferentially spaced primary air inlet openings I3,

and above said ring II, is formed with secondary air inlet perforations l4.

An air jacket l5 encloses the pot 5, said jacket comprising a cylindrical side wall l6 spaced outwardly from the pot side wall I, and a bottom I1 spaced downwardly from the pot bottom 6. Di-

' rectly above its bottom H, the jacket I5 is provided with an inlet l 8 for air under pressure from a blower. The upper end of the wall l6, in the present disclosure, is provided with-an inwardly projecting flange l9 upon which the flange 9 of the pot 5 rests, the two flanges thus closing the upper end of the space between the side walls 7 and I6.

A cylindrical shield wall 20 is interposed between the pot side wall 1 and the jacket side wall I6 and terminates below the flanges 9 and 9. Th'm'shield wall 20 divides the space between the two side walls I and .I 6, into an up-flow passage 2| and a down-flow passage 22 which communicate with each other at their upper ends. The lower end of the up-flow passage 2| communicates with the lower portion of the air jacket l5, and the lower end of the down-flow passage 22 is closed by the peripheral portion of a bottom plate 23, said bottom plate being joined to the lower edge of the shield wall. 20 and being disposed in contact with the lower side of the bottom 6 of the pot 5.

I provide communicatin means between the up-flow passage 2| and the primary air inlet openings l3. which means segregates these open ings l3 from the down-flow passage 22. In the present construction, the means in question consists of substantiall conical nipples 24 stamped inwardly from the jacket side wall l6 and abutting the pot side wall 1. Said nipples 24 decline inwardly to direct the primary air downwardly through the openings l3 and toward the bottom of the pot. The inner ends of these nipples di- -rectly communicate with the primary air inlet openings l3 and these openings also preferably decline inwardly as shown more particularly in Fig. 2, to direct the primary air downwardly toward. the bottom 6 of the pot 5.

I also provide air-flow restricting means so associated with the up-flow passage 2| as to slow down the discharge of air from said up-flow passage 2| into the down-flow passage 22, during high-flame operation of the burner, at which agcaoao erable pressure and at relatively highkvelo'citm, from the inlet l8. Thus, the airpressure in the.

will be greater than that above said means, with the result that the primary air will be forced'in abundance through the nipples 2i and openings l3, thus supporting such thorough combustion in the bottom zone of the pot 5, that no pool of oil will accumulate therein. Contributing to this result, is the bottom plate 23 which contacts with jecting inwardly from the jacket side wall l6- into close relation with the shield wall 20. In the present disclosure, this choke ring 25 is somewhat below the upper end of the wall 20, but it could be located either higher or lower.

During high-flame operation of the burner, the primary air is forced in abundance through the nipples 24 and primary air inlet openings l3 to support thorough combustion of the fuel entering through the inlet 8, and due to this thorough combustion and the protection of the pot bottom 6 against the cooling effect of the ingoing air, by means of the plate 2.3, unusually high temperature will exist in the bottom zone of the pot, with the result that the ingoing fuel will be rapidly vaporized instead of accumulating in a jacket l5, below the air-flow restricting means,

ary air to the pot through the openings M, to

support thorough combustion. When the supplies of air and oil are adjusted for low-flame, there is no pool of oil left upon the bottom of the pot which must first be burned out. as is the case with most pot type burners. This action allows a much larger volume of oil to be vaporized in a given size pot than has been possible heretofore and still maintains the same low fire efficiency. In other burners, as soon as adjustment is made for low flame, the air pressure within the jacket 15 is insufficient to supply ample air through the openings i3 to support combustion of a relatively large quantityor pool of oil, with the result that heretofore smoking of the burner has occurred, creating soot and carbon. With the improved construction, while the air pressure below the choke ring (at low flame) is not appreciably higher than that above said choke ring, due to the very low velocity of the ingoing air and its relatively slight pressure, nevertheless sufficient air can enter through the primary openings l3 to support thorough combustion of the mere trickle of oil then entering, and no smoking and carbonizing occurs.

From the foregoing, taken in connection with the accompanying drawings, it will be seen that novel and advantageous provision has been made for carrying out the objects of the invention, and

, while preferences have been disclosed, attention is again invited to the possibility of making variations within .the scope of the invention as claimed.

I claim: 1. An oil burner comprising a not having an oil 4 inlet, said pot comprising a bottom and a side wall, said side wall having a series of primary air inietopenings in its lower portionand having secondary air inlet perforations above said primary air inlet openings, an air supply jacket enclosing said pot, said Jacket-having a side wall surrounding and spaced from said pot side wall and having a bottom spaced downwardly from said pot bottom, said jacket having an inlet in its lower portion for admitting air under pressure and being closedat its upper end, a continuous shield wall in the space between said side walls of said pot and jacket and dividing said space into an up-flow passage adjacent said jacket side wall and a down-flow passage adjacent said pot side wall, the lower end of said up-flow passage being open to receive air from the lower portion of said jacket, the lower end of said shield cooperating with said pot to close the lower end of said downflow passage, the upper ends of said up-fiow and down-flow passages being in communication with each other, primary air conducting means placing said up-fiow passage in communication with said primary air inlet openings and segregating these openings from said down-flow passage, and airflow restricting means above said air-conducting means and so associated with said up-fiow passage as to cause lower air pressure in the upper portion of said jacket than in the lower portion thereof when air is supplied to said jacket under relatively high pressure; whereby, while the air and oil supplies remain adjusted for high-flame, sufl'icient air will be forced through said primary air inlet openings to insure combustion of all oil then entering the pot, thereby preventing a pool of oil from being left in said pot when the supplies of air and oil are reduced for low fiame.

2. A structure as specified in claim 1; said primary air-conducting means consisting of nipples projecting inwardly from said shield wall and abutting said pot side wall.

3. A structure as specified in claim 1; said air flow restricting means consisting of a choke ring on said jacket side wall and extending into close relation with said shield wall.

4. A structure as specified in claim 1; together with a bottom plate secured to the lower 'end, of said shield wall and contacting with the REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 939,415 Heindel Nov. 9, 1909 1,512,869 Valjean- Oct. 21, 1924 2,225,467 Breese Dec. 17,- 1940 2,261,814 Suchland' Nov. 4, 1941 2,290,544 De Lancey July 21, 1942 2,313,568

' Miller Mar. 9, 1943 

